Glass-drawing apparatus



Patented Jan. 26, 1926.

UNITED STATES PATENT OFFICE- WILLIAM L. MONRO, OF PITTSBURGH,PENNSYLVANIA, .ASSIGNOR TO WINDOW GLASS MACHINE COMPANY, OF PITTSBURGH,PENNSYLVANIA, A CORPORATION OF NEW JERSEY.

GLASS-DRAWING APPAATUS.

Applipation led November 6, 1922. Serialy No. 599,236.

To all whom it may concern: f

Be it known that I. WILLIAM I1. MoNRo, a citizen of the United States,residing at Pittsburgh, in the county of Allegheny and State ofPennsylvania, have invented a new and useful Improvement inGlass-DrawingApparatus, of which the following is a full, clear, and exactdescription.

This invention relates to glass drawing apparat-us, and moreparticularly to the Lubbers venting system used in the drawing of glasscylinders. While the original Lubbers system of venting was effectualinreducing bumps or pulsations to within commercial flattening limits,this invention still further reduces such pulsations, and is effectiveto produce a more uniform cylinder under varying operating conditions.

In the co-pending application of Monro, Clark and Pierce, Serial No.231,332, filed April 29, 1918, there is shown a venting system in whicha jet of air is forced into a venting chamber of larger cross sectionalarea. than the jet, thence through a long enclosed conduit to thecylinder. I have discovered that pulsations are still further re* ducedor avoided if the venting chamber is `moved to a position adjacent thebait.

Another 'distinguishing feature of the present invention is the locationof the venting opening with respect to the jet opening. I have foundthat the action of the vent is rendered much more sensitive if the ventopening extends at least as far as the plane of the air jet opening.

In the accompanying drawings, illustrating the preferred embodiment ofmy invention,

Figure 1 is a view, partly broken away, showing my improved vent appliedto the usual form of blow-pipe;

Figure 2 is a detail sectional view of a portion of Figure 1;

Figure 3 is a section, to reduced scale, on the line III- III of Figure2;

Figure 4 is a view corresponding to Fig ure 3, but showing a two-holeform of vent;

Figure 5 is a detail sectional view showing a slightly modified form ofapparatus; and

Figure 6 is a detail sectional View showing another modification.

In the preferred embodiment of the invention, air is supplied from anair line, not shown, through the usual ball connecd tion 2 of ablow-pipe 3, thence through a restrictor 4 into a venting chamber 5. Theventing chamber 5 is located adjacent the drawing bait 6. v

A venting opening 7 is provided in the side wall of the chamber 5. 7 maybe of any shape, but it should extend at least as far as, and preferablybe tangent to, or terminate in, the plane of the jet openlng. I havefound that the sensitivity of thevent is greatly increased by such anarrangement. The form shown in Figure 5 has also given good results. Inthis form the restrictor 4 projects slightly into the chamber. While thebest results are apparently attained when the vent opening terminates inthe plane of the jet opening, it may be -shifted slightly upwardlywithout materially affecting the sensitivity. In other words, the jetopening should be at or below the upper edge of the vent opening. l

The effect of the restrictor 4 is to cause the air to enter the chamber5 in jetform. This results, I believe, in the formation of regions ofsub-atmospheric pressure adjacent the chamber walls lateral to the airstream, as indicated by dotted section lines in Figures 2, 3 and 4. Thespace thus taken up I have designated generally as a pocket, since thereis a partially enclosed space back of the current of air moving throughthe chamber. This tendency to create a region of reduced pressure is ofcourse obviated on one side by the vent opening, where atmosphericpressure will always tend to prevail. These two conditions, I believe,cause the air stream to be drawn slightly out of line toward the pocket,and any variation in pressure in the cylinder is reflected in theswaying of the air stream back and forth. This swaying causes greater orless air How through the vent opening 7 dependin on whether the airstream sways towar or away from the vent, and serves to very accuratelyregulate the cylinder pressure. I do not, however, limit myself to thistheory.

In Figure 4 a modified form of apparat-us embodymg two vent openings 7is shown. The vents are so disposed with re's ect to the chamber wallthat each has a pocet opposite it. Such a form has" been foundsatisfactory in gractice, whereas Aother forms, in which one TheopeningY 'ol'er was placed opposite the' other, thus eliminating thepocket, have not been satisfactory.

In Figure 6, an air supply pipe 3a of smaller cross sectional area thanthe chamber 5 is used to give the jetaction which I secure in thepreferred form by the restrictor t.

While I have shown the preferred form of my invention, it will beunderstood that it is not limited to the illustrated details, but may beembodied in other constructions without departing from the spirit of theinvention or the scope orn the following claims.

I claim:

l. In apparatus for drawing glass cylinders, a bait, a. chamber adjacentthe bait, and a. nozzle of smaller cross sectional area than the chamberadapted for the discharge of air in jet form through the chamber andinto the bait, the chamber havino' a substantially continuous wall atone sizde of the path of said air jet and having an opening oppositesuch wall, substantially as described.

2. In apparatus for drawing glass cylinders, a chamber through which airis supplied to the cylinder being drawn, the chamber having an air inletopening which is of smaller cross sectional area than the chamber andadapted to deliver air in jet form, the chamber also having a ventingopening extending at least as far as the plane of the air inlet opening,substantially as described.

3. In apparatus for drawing glass cylinders, achamber through which airis Vsupplied to the cylinder being drawn, the chamber having an airinlet opening which is of smaller cross sectional area than the chamberand adapted to deliver air in jet form, the chamber also having aventing opening terminating in the plane of the air inlet opening,substantially as described.

4. In apparatus for drawing glass cylinders, a bait and a chamberimmediately adjacent thereto through which air is supplied to thecylinder being drawn, the chamber having an air inlet opening which isof smaller cross sectional area than the chamber and adapted to deliverair in jet form, the chamber also having a` venting opening terminatingin theplane of the air inlet opening and having a pocket opposite theventing opening, substantially as described.

In testimony whereof I have hereunto set my hand.

WILLIAM L. MONRO.

